Rock deformation mechanism of northern Altun margin-Evidence from X-ray fabric analysis

This paper reports the geological tectonic settings and regional stratigraphic rocks of northern Altun marginal area. Based on the quartz and sericite X-ray perofabrics analysis of altered deformed granite, granitic mylotite, deformed acidic volcanic rock and deformed dacitic tuff from this area, the authors have drawn the following conclusions:①The rock deformation of this area is relatively apparent; ②Sericite is parallel to the schistosity and shows a great orientation in the alignment which reflects the strong deforma-tion along the EW-trending tectonic deformed belt; ③Quartz is mainly deformed along its basal or basal-near glide system and is combined with prismaticⅠandⅡglide system; ④The deformation mechanism of northern Altun area happened at a medium-shallow depth of 10~15km with a low-middle temperature of 250~350℃and a low pressure of 0.25~0.40GPa; ⑤According to the features of X-ray perofabrics analysis and schistosity, the authors hold that this ductile deformation moved in a right-lateral way. All this is consistent with the features of ductile-brittle deformation zone formed by plate collision belt and oceanic crust closure in Dapinggou area of northern Altun.